/Engine/Plugins/Interchange/Runtime/Source/Import/Public/MaterialX/MaterialXUtils/MaterialXSurfaceShaderAbstract.h
Add aFLinearColorattribute to a shader node only if its value taken from the input is not equal to its default value. Return false if the attribute does not exist or if we cannot add it
true if the attribute was successfully added
bool AddLinearColorAttribute ( MaterialX::InputPtr Input, const [FString](API\Runtime\Core\Containers\FString) & InputChannelName, [UInterchangeShaderNode](API\Plugins\InterchangeNodes\UInterchangeShaderNode) * ShaderNode, const [FLinearColor](API\Runtime\Core\Math\FLinearColor) & DefaultValue ) const